Auxiliary device for the production of hollow crowns of teeth from cast metal



March 5, 1929. w. KOPP 1,704,006

mumm DEVICE FOR THE rnonucnou or THE} HOLLOW CRQWNS OF TEETH FROM CAST METAL Filed June 14, 1926 Patented Mar. 5, 1929.

I ourrsn srAEs PATENT OFFICE.

"WIL ELM KGPP, or wn isnonn, GERMANY.

AUXILIARY DEVICE non run rnonuorion OF HOLLOW onowlvs or TEETH FROM CAST METAL.

Application filed June 14, 1926, Serial No. 116,027, and in Germany February 24, 1926.

The present invention relates to an auXiliary device for the production of hollow moulds for the manufacture of crowns for teeth from cast metal. The method of pro ducing (hollow) gold crowns which has hitherto been generally usual has consisted in utilizing; so -called drawing or stamping apparatus for making the crowns. Edince the casting process has been introduced into dens tistry it has been the endeavor to discover a process permitting" the productimi of gold crowns by said casting process. an methods hitherto employed, however, have proved to be imperfect and too tedious. a

Now the present invention enables any person versed in the art to cast in the shortest time a crown which will suit all recuiirements.

The accompanying drawings show means for carrying the invention into use and Figure 1 is a side elevation'otthe complete device and Figure 2 shows the rated.

The present invention consists in providing a pattern for the production of a thinwalled mould for the crown of the tooth w iich has the form of a rod and is made of steel or other material and which, as the ac essential parts sepacompanying; drawing shows, is separable.

lomritiildinally into three or more parts. One end of this red has the form oi? a-human tooth while the other end is formed as a smooth stem. 'lhe several parts 1 and 2 of the pattern for the production of the mould for the crown are accurately ground on to one another at their contact faces and are held to nether in their correct positions by means of a sleeve or other closure device 3.

The method of producing a thin-walled would for the nmnu'facture of a crownby means oi the pattern therefor is briefly as follows: The readily lubricated crown-end l oi the pattern is dipped into molten wax so that it becomes covered with a thin layer of wax. When the pattern has been withdrawn from the molten wax, this th1n layer of war; becomes stiii so as to form a thin-walled mould upon the pattern. Theremoval of. i

this wax-mould oi the pattern is then etlected by taking off the closure device 3 which holds the several parts 1 and of the patterntonether, whereupon the several parts in the first place the central part 2, is withdrawn from the wax-mould. The wax-mould soiobtained is emheddedand the cast made therefrom by the usual method. i I

The crowns produced by means of the pattern of the crown possess a correctly anatomical form and have no seam or soldered joint. A further advantage is that places which are to be speciallystrengthened or the masticating faces, the backs, the cutting edges and so on of teeth which are to be given a special form may be varied by suitably modelling and applying wax on the mould before the latter is removed from the pattern. I

The patterns for the crowns of teeth may be produced for any kind of tooth in the human jaw (for upper and lower incisors,' bicuspids and molars).

Having now' particularly described 1 and and in what manner the same'is to be performed I declare that what I claim is:

1.. Process for forming moulds for the manufacture of hollow crowns of teeth from cast metal, consisting in forming a pattern for he crown oi a more from several longitudinal parts, dipping this pattern into molten wax'so as to coat it with a thin layer of wax withdrawing; the pattern together with this layer of wax from the molten ascertained the nature of my said invention,

wax, render-ing still this layer of wax so as to term a hollow mould removing the pattern from this hollow mould by successively withdrawing); the middle audthen the other longitudinal partsof the pattern.

Pattern for the productioir of thinvided in the longitudinal direction (it the teeth, a removable connecting device hiildina' together these bars. 7 i in testimony whereof 1 afiix my signature,

WILHELM KOP'P, 

